If you want a superb garage in Essex, then try Stancombe Vehicle Engineering, near Orsett. Colin races in the Clio Cup (with a 4 car team) and has been in Motor Racing for 20 odd years. You couldnt really find a better/more knowledgable mechanic.
He lowered my 172 on Eibachs (which I supplied) for under £100. And he has a special mod for the rear which dramatically improves the handling!!!